The Lost River sucker was federally listed as endangered in
1988. A recovery plan was published in 1993. Critical habitat was
proposed in 1994, but not designated. A status review was conducted
in 2004, and a five-year review was done in 2007.

Historical Status and
Current Trends

Early records indicate that Lost River suckers were once widespread
and abundant in the upper Klamath Basin of Oregon and California.
This area historically contained over 350,000 acres of wetlands
and floodplains. These wetlands protected sucker habitat by
controlling erosion, recycling organic and inorganic nutrients,
and maintaining water quality. Because suckers were historically
very abundant, they were a major food source for Native Americans
and local settlers in the late 1800s. Canneries were established
along the Lost River to process suckers into oil, dried fish,
and other products. However, agricultural development and associated
water and land use changes in the basin have contributed to
the significant loss of wetland habitat and a significant decline
in sucker populations. Although overharvesting and pollution
may have played a role in the species decline, it is believed
that the combined effects of the construction of dams, the draining
or dredging of lakes, and other alterations of natural stream
flow have reduced the reproductive success of Lost River suckers
by as much as 95 percent through the degradation of suitable breeding
habitat. At the time the Lost River sucker was listed as endangered,
it was noted that there had been no significant addition of
young into the population in 18 years.

Currently, the Lost River sucker occupies only a fraction of
its former range and is restricted to a few areas in the Upper
Klamath Basin, such as the drainages of Upper Klamath Lake,
Tule Lake, and Clear Lake. Poor water quality, reduced suitable
habitat for all sizes and ages, and the impacts of non-native
fishes continue to threaten remaining Lost River sucker populations.

Description and Life
History

Locally known as mullet, the Lost River sucker is a large,
long-lived sucker that can reach 43 years of age. It has unique
triangular-shaped gill structures which are used to strain a
diet of detritus (decomposing organic matter), zooplankton (tiny
floating aquatic animals), algae, and aquatic insects from the
water. Lost River suckers typically begin to reproduce at nine
years, when they first participate in spawning migration. Adult
suckers migrate from the quiet waters of lakes into fast moving
streams from March through May in order to spawn. They may also
spawn in lakeshore springs from February to mid-April when the
water temperature is a constant 15 C (60 F). Thousands of eggs
(from 44,000 for smaller fish to 218,000 for larger suckers)
are typically laid near the stream bottom in areas where gravel
or cobble is available. Once the eggs hatch, the larval fish
begin their migration back to calmer waters. They generally
migrate at night and stay in shallow, shoreline areas and in
aquatic vegetation during the day. Upon their return to the
lake, larvae may be preyed upon by largemouth bass, yellow perch,
or other non-native predatory fish, and larger juveniles may
compete for food with non-native fishes such as fathead minnows,
yellow perch, and others.

Habitat

The Lost River sucker dwells in the deeper water of lakes and
spawns in springs or tributary streams upstream of the home
lake. Areas with gravel or close-set stone ("cobble")
bottoms at springs or in moderate to fast-flowing springs are
preferred for spawning. In addition, the spawning streams have
a fairly shallow shoreline with abundant aquatic vegetation;
these areas provide a safe haven for the young larvae during
their journey back downstream to their home lakes or the deep,
quiet waters of rivers.

Reasons for Decline

Although a number of factors have contributed to the decline
of the Lost River sucker, habitat degradation is considered
the primary cause. Streams, rivers, and lakes have been modified
by channelization and dams. Grazing in the riparian zone has
eliminated streambank vegetation, and has added nutrients and
sediment to river systems. Eggs and larvae, for example, suffocate
when the water is cloudy, or dry out or get eaten by other fish
when they are not protected by aquatic vegetation. Loss of streambank
vegetation due to overgrazing, logging activities, agricultural
practices, and road construction has also led to increases in
stream temperatures, high levels of nutrients (which encourages
the buildup of excess algae and bacteria), and serious erosion
and sedimentation problems in streams. Such water quality problems
have reduced the availability of suitable Lost River sucker
habitat and have resulted in major fish mortality. Entire age
classes of young suckers are routinely lost due to poor water
quality conditions. As a result, few young suckers survive to
sexual maturity, and therefore, do not increase the population
size. Other factors affecting the decline of the Lost River
sucker include previous overharvesting, chemical pollution from
pesticides, herbicides, and forestry practices, and predation
and competition from native and non-native fishes such as largemouth
bass, blue chub, yellow perch, fathead minnows, and rainbow
trout.

Conservation Measures

Conservation efforts for the Lost River sucker focus on the
re-establishment of a more naturally functioning ecosystem in
the Klamath Basin. Fencing portions of streams to reduce cattle-caused
erosion, replanting streambanks with native vegetation, improving
forestry and agricultural practices, and assuring adequate water
levels in reservoirs will contribute to the recovery of this
species. Through coordination of the actions of land use agencies
and private landowners, further degradation of sucker habitat
can be avoided and steps can be taken to improve current conditions.
By minimizing the impacts of future modifications to spawning
habitat and restoring waters to a more natural state, recovery
of Lost River sucker populations is possible in the Klamath
Basin.

References and Links

U.S. Fish and Wildlife Service. 1988. Determination of Endangered
Status for the Shortnose Sucker and Lost River Sucker. FR
53:27130-27134.